System for fabricating semiconductor components

ABSTRACT

A method for fabricating semiconductor components, such as BGA packages, chip scale packages, and multi chip modules, includes the steps of cutting decals from ribbons of adhesive tape, and then attaching a semiconductor die to a substrate using the decals. A system for performing the method includes a tape cutting apparatus configured to cut the decals from the tape without wasted tape, and then to apply the cut decals to the substrate. A first finished dimension (e.g., width) of the decals is determined by a width of the tape, and a second finished dimension (e.g., length) of the decals is determined by indexing the tape through a selected distance. The tape cutting apparatus includes cutters configured to move through guide openings to cut and apply the decals to the substrate. The guide openings align the tape to the cutters, and also align the cut decals to the substrate. The system also includes a substrate handling apparatus configured to index and position the substrate relative to the guide openings.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of Ser. No. 09/356,267, filed on Jul. 16,1999, U.S. Pat. No. 6,281,044 B1, which is a continuation-in-part ofSer. No. 09/033,497, filed on Mar. 2, 1998, U.S. Pat. No. 6,025,212,which is a continuation of Ser. No. 08/509,048, filed on Jul. 31, 1995,abandoned.

FIELD OF THE INVENTION

This invention relates generally to semiconductor manufacture, andspecifically to an improved method and system for fabricatingsemiconductor components.

BACKGROUND OF THE INVENTION

Semiconductor dice are used to construct various semiconductorcomponents, such as semiconductor packages and multi chip modules. Thesesemiconductor components typically include a substrate on which baresemiconductor dice are mounted. For example, conventional plasticsemiconductor packages can include substrates in the form of metalleadframes. During a packaging process the bare dice are attached andelectrically connected to the leadframes, and then encapsulated in aplastic resin.

Besides leadframes, other types of substrates are used to constructsemiconductor components. For example, other types of semiconductorpackages, such as “BGA packages” and “chip scale packages”, includesubstrates which can comprise a glass filled plastic, such as FR-4, orFR-5, or in some cases silicon, or ceramic. Multi chip modules andcircuit boards, can also include plastic, silicon, or ceramicsubstrates, on which semiconductor dice, as well as other electroniccomponents, are mounted.

During fabrication of a semiconductor component the dice are attached tothe substrate. One method for attaching the dice to the substrate is byforming an adhesive layer between the dice and the substrate. Forexample, die attach adhesives, such as epoxy and silicone, can be usedto back bond dice to substrates. Typically, the adhesive is dispensed inviscous form from a pressurized nozzle, and then cured to harden.However, for some applications it is not practical to use an adhesivebecause the viscous material may undesirably adhere to the surfaces ofbond pads, and other electrical elements on the die or substrate, andadversely affect the electrical characteristics of the component. Alsofor some applications, it may not be possible to uniformly form theadhesive layer with a required planarity and geometrical configuration.

Another technique for attaching dice to lead frame substrates employsadhesive tape. For example, during fabrication of a lead-on-chipsemiconductor package, semiconductor dice are attached to a metalleadframe using double sided adhesive decals. With a typicallead-on-chip fabrication process the decals are punched with a requiredperipheral configuration from a length of tape. Portions of the tapethat do not become part of the decal are then discarded.

While adhesive tape has been used successfully in the manufacture ofplastic semiconductor packages constructed with metal lead frames, ithas typically not been used in the volume manufacture of other types ofsemiconductor components. The present invention is directed to a methodand system for fabricating various types of semiconductor componentsusing adhesive tape to attach one or more semiconductor dice to asubstrate. In addition, the present invention makes decals withoutwasted tape, and with accurate alignment of the decal, the substrate,and the die to one another.

SUMMARY OF THE INVENTION

In accordance with the present invention, an improved method and systemfor fabricating semiconductor components, such as packages, multi chipmodules, and printed circuit boards, are provided.

In a first embodiment the method is used to fabricate a BGA package. TheBGA package includes a substrate, a semiconductor die attached to thesubstrate, and one or more adhesive decals attaching the die to thesubstrate. In this embodiment the substrate comprises an organic polymersuch as bismaleimide-triazine, epoxy or polyimide, reinforced with glassfibers. The substrate is provided as a strip of material, on whichmultiple BGA packages are formed, and then singulated by cutting orshearing.

The method uses one or more continuous ribbons of tape which are cutinto decals, and then applied to required areas of the substrate. Thetape can comprise a double-sided, multi-layered adhesive tape, such aspolyimide film coated on both sides with an adhesive, or alternately asingle layer of adhesive material configured as tape. The decals are cutand applied to the substrate by indexing lengths of the tape into guideopenings, aligning the substrate to the openings, and then movingcutters through the guide openings to cut and place the decals on thesubstrate. A finished dimension (e.g., width) of each decal is the sameas a width of the tape. Another finished dimension (e.g., length) ofeach decal is controlled by cutting an indexed length of the tape. Usingthis method there is no wasted tape. In addition, there are only two cutedges per decal, and only one cut is required for each index of the tapeand substrate.

A system for performing the method of the invention includes thesubstrate, the die, and a tape cutting apparatus configured to cut, andapply, the decals to the substrate. The system also includes a substratehandling apparatus configured to align the substrate during cutting andapplying of the decals.

The tape cutting apparatus includes: a support frame for rotatablymounting one or more reels of adhesive tape of a desired width; a tapeguide for guiding continuous ribbons of tape from the reels into guideopenings for cutting; a pair of feed rollers for continuously feedingand indexing the ribbons of tape into the guide openings; and a cutterassembly adapted to move through the guide openings to cut the decalsfrom the ribbons of tape held in the guide openings, and to apply thedecals in a desired pattern to a die mounting area of the substrate.

The substrate is positioned proximate to the guide openings of thecutter assembly by the substrate handling apparatus. The substratehandling apparatus also indexes the substrate to align selected diemounting areas on the substrate to the cutter assembly for applicationof the cut decals.

In a second embodiment the method is used to fabricate a chip scalepackage comprising a substrate, a semiconductor die attached to thesubstrate, and one or more cut decals attaching the die to thesubstrate. In this embodiment the substrate is provided as a silicon,ceramic or plastic panel on which multiple chip scale packages areformed, and then singulated. In a third embodiment the method is used tofabricate a multi chip module, or a printed circuit board, comprising asubstrate on which multiple semiconductor dice are attached using cutdecals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a plan view of a strip containing multiple substratessuitable for fabricating BGA packages in accordance with a firstembodiment of the invention;

FIG. 1B is a bottom view of the strip;

FIG. 1C is an enlarged portion of a substrate on the strip taken alongsection line 1C—1C of FIG. 1A;

FIG. 1D is a cross sectional view of the substrate taken along sectionline 1D—1D of FIG. 1C;

FIG. 1E is a cross sectional view of the substrate taken along sectionline 1E—1E of FIG. 1C;

FIGS. 2A-2C are schematic cross sectional views illustrating steps inthe first embodiment of the method of the invention during fabricationof a BGA package;

FIG. 2D is a plan view taken along section line 2D—2D of FIG. 2A;

FIG. 2E is a plan view taken along section line 2E—2E of FIG. 2B;

FIG. 2F is a plan view taken along section line 2F—2F of FIG. 2C;

FIG. 3 is a side elevation view of a tape cutting apparatus constructedin accordance with the invention for cutting and applying decals to thesubstrate;

FIG. 4 is a plan view of a system for fabricating semiconductorcomponents in accordance with the invention;

FIG. 5 is an end view taken along section line 5—5 of FIG. 4;

FIG. 6 is an exploded view of a portion of the tape cutting apparatus ofFIG. 3 illustrating a tape cutter assembly of the apparatus;

FIG. 7A is a schematic plan view illustrating steps in a secondembodiment of the method of the invention during fabrication of chipscale packages;

FIG. 7B is an enlarged cross sectional view taken along section line7B—7B of FIG. 7A illustrating a completed chip scale package;

FIG. 7C is a plan view of an alternate embodiment system constructed inaccordance with the invention for fabricating the chip scale package ofFIG. 7B;

FIG. 8A is a schematic plan view illustrating steps in a thirdembodiment of the method of the invention during fabrication of a multichip module;

FIG. 8B is an enlarged cross sectional view taken along section line8B—8B of FIG. 8A illustrating a die on the multi chip module; and

FIG. 8C is a plan view of an alternate embodiment system constructed inaccordance with the invention for fabricating the multi chip module ofFIG. 8A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1A-1E, a polymer strip 12 comprising a plurality ofsubstrates 14 is illustrated. As will be further explained, the polymerstrip 12 can be used to fabricate a plurality of BGA packages 16 (FIG.2C) in accordance with the invention. In FIGS. 1A-1E, the polymer strip12 is illustrated prior to attachment of a plurality of semiconductordice 10 (FIG. 2B) to the substrates 14.

The polymer strip 12 comprises an electrically insulating polymermaterial, such as an organic polymer resin reinforced with glass fibers.Suitable materials include bismaleimide-triazine (BT), epoxy resins(e.g., “FR-4” and “FR-5”), and polyimide resins. These materials can beformed. with a desired thickness, and then punched, machined, orotherwise formed with a required peripheral configuration, and withrequired features. A representative thickness of the polymer strip 12can be from about 0.2 mm to 1.6 mm.

Each substrate 14 is a segment of the polymer strip 12, and willsubsequently be separated from the adjacent substrates 14 to form a BGApackage 16BGA (FIG. 2C). In the illustrative embodiment there areeighteen substrates 14 on the polymer strip 12. However, this number ismerely exemplary and the polymer strip 12 can include a fewer, orgreater, number of substrates 14. The polymer strip 12 facilitates thefabrication process in that different operations, such as die attach,and wire bonding, can be performed at the same time on each of thesubstrates 14.

Each substrate 14 includes a first surface 18 (FIG. 1A), and an opposingsecond surface 20 (FIG. 1B). The first surface 18, and the secondsurface 20, are the major planar surfaces of the substrates 14. Eachsubstrate 14 also includes a pattern of conductors 22 (FIG. 1C) formedon the first surface 18 thereof, and a corresponding die attach area 24(FIG. 1B) formed on the second surface 20 thereof.

As shown in FIG. 1A, the polymer strip 12 includes circular indexingopenings 26 formed along the longitudinal edges thereof. The indexingopenings 26 permit the polymer strip 12 to be handled by variousapparatuses such as lead frame handlers, wire bonders, molds, and trimmachinery used during fabrication of semiconductor components inaccordance with the invention. The polymer strip 12 also includeselongated separation openings 28 which facilitate singulation of thesubstrates 14 on the polymer strip 12 into separate BGA packages 16(FIG. 2C). The substrates 14 also include wire bonding openings 30 whichprovide access for wire bonding semiconductor dice 10 (FIG. 2B) to thepatterns of conductors 22 on the substrates 14.

Referring to FIG. 1C, a single substrate 14 and the conductors 22 on thesubstrate 14 are shown in greater detail. The conductors 22 can comprisea conductive metal layer, which is blanket deposited onto the substrate14 (e.g., electroless or electrolytic plating), and then etched inrequired patterns. Alternately, an additive process, such as electrolessdeposition through a mask, can be used to form the conductors 22 inrequired patterns. A preferred metal for the conductors 22 is copper.Other suitable metals for the conductors 22 include aluminum, titanium,tungsten, tantalum, platinum, molybdenum, cobalt, nickel, gold, andiridium. If desired, the substrate 14 and conductors 22 can beconstructed from a commercially produced bi-material core, such as acopper clad bismaleimide-triazine (BT) core, available from MitsubishiGas Chemical Corp., Japan. A representative weight of the copper can befrom 0.5 oz to 2 oz. per square foot.

As shown in FIG. 1C, each conductor 22 includes a wire bonding pad 32and a ball bonding pad 34. The wire bonding pads 32 can subsequently beplated with metals such as nickel and gold to facilitate the wirebonding process. The ball bonding pad 34 can also subsequently be platedwith a solder flux to facilitate attachment of solder balls 36 (FIG. 2C)thereto.

As shown in FIG. 1C, the polymer strip 12 also includes a plurality oftriangular metal segments 38, and a plurality of circular metal segments40 formed on the first surface 18. The metal segments 38, 40 cancomprise a same metal as the conductors 22. The triangular shaped metalsegments 38 function as a pin #1 indicators. The circular metal segment40 functions as alignment fiducials. As shown in FIG. 1B, the polymerstrip 12 also includes a plurality of square metal segments 42 and aplurality of triangular metal segments 38 formed on the second surface20. The square metal segments 42 function as gate breaks for a moldcompound. The triangular metal segments 38 functions as pin #1indicators.

Referring to FIGS. 2A-2C, steps in the method for fabricating the BGApackage 16BGA (FIG. 2C) using the polymer strip 12 and the method of theinvention are illustrated. For simplicity, only one substrate 14 on thepolymer strip 12 is illustrated in FIGS. 2A-2C. However, in actualpractice the steps in the fabrication method are performed on all of thesubstrates 14 on the polymer strip 12 prior to singulation of thepolymer strip 12 into individual BGA packages 16.

Initially, as shown in FIG. 2A, a solder mask 46 can be formed on thefirst surface 18 of the substrate 14. The solder mask 46 includesopenings 48 aligned with the ball bonding pads 34 on the first surface18. In addition, the solder mask 46 includes an opening 50 that exposesthe wire bonding pads 32, and portions of the conductors 22 on the firstsurface 18. The solder mask 46 can be formed by exposing and developinga photoimageable dielectric material, such as a negative or positivetone resist. Suitable resist formulations are manufactured byCiba-Geigy, Shipley and Taiyo America.

As also shown in FIG. 2A, decals 52 are attached to the die attach area24 on the second surface 20 of the substrate 14 using a tape cuttingapparatus 54 (FIG. 3) constructed in accordance with the invention. Thedecals 52 are cut by the tape cutting apparatus 54 (FIG. 3) from alength of tape. The tape can comprise a conventional double sidedadhesive tape comprising a polymer substrate, such as polyimide, coatedon both sides with an adhesive.

Alternately, the tape can comprise a single layer of adhesive material,configured as tape.

As will be further explained, a width of the tape is the same as thewidth of the decals 52. This width, and the length of the decals 52, areselected such that the decals 52 cover selected portions of the dieattach area 24 and the die (FIG. 2E). In the embodiment illustrated inFIG. 2D, the decals 52 have a generally rectangular peripheralconfiguration, and are located along opposing longitudinal edges of thewire bonding opening 30 in the substrate 14. In addition, the width ofthe decals 52 is selected such that die bond pads 56 (FIG. 2B), whichare located along a center line of the die 10, are not covered by thedecals 52.

Referring to FIG. 2B, following attachment of the decals 52 to thesubstrate 14, the die 10 can be attached to the decals 52, and thus tothe substrate 14. A conventional die attach apparatus can be used toattach the die 10 to the decals 52. In addition, the die 10 can beattached to the decals 52 circuit side down, with the die bond pads 56aligned with the wire bonding opening 30 in the substrate 14. As shownin FIG. 2E, a peripheral outline of the die 10 substantially matchesthat of the spaced decals 52.

As also shown in FIG. 2B, wires 58 can be wire bonded to the die bondpads 56 on the die 10, and to the wire bonding pads 32 on the substrate14. A conventional wire bonding apparatus can be used to perform thewire bonding step. In addition, a glob top encapsulant 60 can be formedin the wire bonding opening 30 and on the wires 58. The glob topencapsulant 60 can comprise a curable polymer applied using a nozzle, ora tool, as is conventional in the art.

Referring to FIG. 2C, following wire bonding, a molded encapsulant 62can be formed on the die 10, and on the die attach area 24 of thesubstrate 14. The molded encapsulant 62 can comprise a Novolac basedepoxy formed in a desired shape using a transfer molding process, andthen cured using an oven. As shown in FIG. 2F, the molded encapsulant 62substantially covers the die attach area 24 on the substrate 14.

As also shown in FIG. 2C, following formation of the molded encapsulant62, solder balls 64 can be bonded to the ball bonding pads 34 on thesubstrate 14. A solder reflow process can be used to bond the solderballs 64 to the ball bonding pads 34. Prior to the solder reflowprocess, solder flux can be deposited on the ball bonding pads 34 and onthe solder balls 64. The solder balls 64 can then be placed on the ballbonding pads 34, and a furnace used to form metallurgical solder jointsbetween the solder balls 64 and the ball bonding pads 34. During bondingof the solder balls 64, the openings 48 in the solder mask 46 facilitatealignment of the solder balls 64 to the ball bonding pads 34. Inaddition, in the completed BGA package 16BGA, the solder mask 46insulates adjacent solder balls 64 and insulates the conductors 22 fromthe solder balls.

Referring to FIG. 3, the tape cutting apparatus 54 which is configuredfor fabricating the BGA package 16BGA (FIG. 2C) in accordance with theinvention is shown. The tape cutting apparatus 54 includes: a supportframe 66; a plurality of tape reels 68 freely rotatably mounted to thesupport frame 66 and adapted to supply continuous lengths of adhesivetape 70 for cutting; a pair of tape feed rollers 72, 74 for feeding andindexing the tape 70 for cutting; a tape guide 76 for guiding the tape70 for cutting; and a tape cutter assembly 78 for cutting the tape 70into decals 52 (FIG. 2A).

In the illustrative embodiment, there are two tape reels 68 forsupplying two continuous lengths of tape 70 and two cut decals 52 perdie 10. However, depending on the application, and the number of decalsrequired for each die 10, the method of the invention can be practicedusing a greater or lesser number of tape reels 68.

The support frame 66 includes vertical supports 80 adapted to supportthe tape reels 68 for rotation. The vertical supports 80 include idlerrollers 82 for supporting the tape 70. Each tape reel 68 includes amounting shaft 84 and the vertical supports 80 include bearings 86 forsupporting the mounting shafts 84 for rotation. The mounting shafts 84are removably journaled to the bearings 86 to permit removal andreplacement of the tape reels 68 as the tape 70 on the reels 68 is used.

The tape 70 comprises a flexible polymer material, such as polyimide,coated on both sides with an adhesive. By way of example, one suitabletape 70 is “Hitachi HM 122U” tape manufactured by Hitachi Chemical Co.LTD. This tape has an overall thickness of about 0.0035″ and is coatedwith about a 0.0008″ thick layer of adhesive on both sides. A width ofthe tape 70 is the same as the finished width of the cut decals 52.Accordingly, the width of the tape 70 is selected to form the decals 52with a finished width to cover selected portions of the substrate 14(FIG. 2D). By way of example, a representative width of the tape can befrom 0.047 inches to 0.120 inches. Alternately, the tape can comprise asingle layer of adhesive an adhesive material configured as tape.

As shown in FIG. 3, the tape feed rollers 72, 74 are rotatably mountedon an upper roller mount 88 and a lower roller mount 90 respectively.The tape feed rollers 72, 74 are driveably connected to stepper motors92 adapted to drive the tape feed rollers 72, 74 through predeterminedcomplete or partial revolutions. Each revolution, or partial revolution,of the tape feed rollers 72, 74 moves the tape 70 a corresponding linearamount. The upper tape feed roller 74 is spring loaded in the verticaldirection to permit tensioning of the tape 70 as required. In thismanner the tape feed rollers 72, 74 can feed, or index, a predeterminedlength of tape 70 through the tape guide 76 and into the tape cutterassembly 78 for cutting.

The tape guide 76 is formed with a guide channel 94 for receiving thetape 70 from each tape reel 68. In addition, the guide channel 94 isadapted to maintain a precise spacing and parallel orientation of theribbons of tape 70 as they are fed and indexed by the tape feed rollers72, 74 into the tape cutter assembly 78. In FIG. 4, the upper rollermount 88 and tape feed roller 74 are cut away to show the confinement ofthe tape 70 within the guide channel 94. The tape 70 is fully enclosedby the guide channel 94 from a point just upstream of the tape feedrollers 72, 74 to the tape cutter assembly 78. As will be furtherexplained, the tape cutter assembly 78 is also configured to enclose andguide the tape 70 for cutting.

Referring to FIGS. 4 and 5, a system 44 for fabricating the BGA package16BGA is illustrated. The system 44 includes the tape cutting apparatus54 and a substrate handling apparatus 100. The tape cutter assembly 78of the tape cutting apparatus 54 is configured to cut the decals 52(FIG. 2D) from the ribbon of tape 70, and to press the cut decals 52against the substrate 14. In a subsequent step, the die 10 will bepressed against the decals 52 for securing the die 10 to the substrate14. FIG. 2D shows the relative locations of the decals 52 after beingcut and pressed by the tape cutter assembly 78 to the substrate 14. Inthe illustrative embodiment a pair of decals 52 are applied to thesubstrate 14. Alternately a greater or lesser number of decals 52 can beapplied to the substrate 14. Furthermore, the decals 52 can be appliedto other portions of the substrate 14, and can have other peripheralconfigurations than shown.

The substrate handling apparatus 100 is configured to index and alignthe polymer strip 12 and the substrate 14 for application of the decals52. Specifically, at the same time that the ribbons of tape 70 are fedinto the tape cutter assembly 78, the polymer strip 12 containing thesubstrate 14 is also fed and indexed into the tape cutter assembly 78 bythe substrate handling apparatus 100. The relative position of thepolymer strip 12 with respect to the ribbons of tape 70 is clearly shownin FIG. 4. In general, the orientation and direction of movement 96 ofthe polymer strip 12 is generally perpendicular to the orientation anddirection of movement 98 of the ribbons of tape 70. The polymer strip 12is indexed into the tape cutter assembly 78 such that one die attacharea 24 (FIG. 1B) at a time is positioned for the simultaneousapplication of the cut decals 52 (FIG. 2D).

The substrate handling apparatus 100 can comprise a conventionalleadframe handling apparatus. A suitable leadframe handling apparatus ismanufactured by ESC Manufacturing, Inc., Ivyland, Pa., and is designateda Model 2000 CA. As shown in FIG. 5, the substrate handling apparatus100 guides and indexes the polymer strip 12 to a location proximate tothe tape cutters 106 suitable for applying the cut decals 52 to thesubstrate 14. As also shown in FIG. 5, the substrate handling apparatus100 can include a heat block 102 to provide the heat necessary toactivate the adhesive on the tape 70, and to hold the polymer strip 12down as the decals 52 are applied by the tape cutter assembly 78 to thesubstrate 14.

Referring to FIG. 6, components of the tape cutter assembly 78 are shownin at exploded view. The tape cutter assembly 78 includes a cutter base104; a pair of tape cutters 106 mounted for reciprocal movement withrespect to the cutter base 104; and a pair of guide openings 108 foraligning the tape 70 with the tape cutters 106 for cutting.

The cutter base 104 is formed as a solid metal block and includesdovetails 110 on either side configured for attachment to the tape guide76 (FIG. 3), and to a mounting block 112 (FIG. 3) of the support frame66. The cutter base 104 also includes separate entrance channels 114separated by a partition 116. The entrance channels 114 are sized forreceiving and maintaining separation of the ribbons of tape 70. Thepartition 116 is sized to maintain a desired separation between theribbons of tape 70, which in the illustrative embodiment isapproximately equal to the width of the wire bonding opening 30 (FIG.2D). A tape lead-in member 118 attaches to the cutter base 104 to coverthe entrance channels 114 and form spaced rectangular passages separatedby the partition 116.

As also shown in FIG. 6, a rectangular groove 120 is formed in thecutter base 104 wherein a cutter block 122 is mounted. The ribbons oftape 70 are guided by the entrance channels 114 under the lead-in member118 and under the cutter block 122. As clearly shown in FIG. 5, thelead-in member 118 is tapered to guide the tape 70 under the cutterblock 122. The cutter block 122 is adapted to hold the uncut ribbons oftape 70 down as the decals 52 (FIG. 2D) are simultaneously cut andpressed against the substrate 14.

The guide openings 108 for the cut decals 52 extend through the fullthickness of the cutter base 104. The guide openings 108 are adapted toalign the ribbons of tape 70 with the tape cutters 106 and to align thecut decals 52 with the substrate 14. As clearly shown in FIG. 5, thetape cutters 106 are adapted to move through the guide openings 108 tocut the ribbons of tape 70. Furthermore, the tape cutters 106 areadapted for movement past an upper surface 126 of the cutter base 104 topress the cut decals 52 against the substrate 14, which is held againstthe heat block 102. The tape cutters 106 include vacuum passages 128 inflow communication with a vacuum conduit 130 (FIG. 5). The vacuumpassages 128 apply a vacuum force to the decals 52 for securing the cutdecals 52 to the tape cutters 106 as the cutters 106 are extended topress the decals 52 against the substrate 14. The vacuum conduit 130(FIG. 5) is in flow communication with a vacuum source (not shown) andsuitable control valves (not shown) for effecting cycling of the vacuumto the vacuum passages 128 as required.

A peripheral outline of the decals 52 matches the peripheral outline ofthe end surfaces 132 of the tape cutters 106, and also the peripheraloutline of the guide openings 108. In the illustrative embodiment thedecals 52 have a generally rectangular peripheral shape. However, otherperipheral shapes such as a polygonal, square, circular, or oval arealso possible. Depending on the dimensions of the die 10, the tapecutters 106 and guide openings 108 can be dimensioned as required.

As also shown in FIG. 6, the tape cutters 106 are attached to a mountingplate 134 and to a mounting shoe 136. A dowel pin 138 secures the tapecutters 106 to one another. and to the mounting plate 134. The mountingshoe 136 includes a rectangular opening 140 for the tape cutters 106.Sleeve bearings 142 are attached to the mounting shoe 136 and mountingplate 134 and slide over guide posts 144 attached to the cutter base104. Retaining rings 146 are attached to the guide posts 144 to preventthe sleeve bearings 142 from sliding off the guide posts 144. Theassembled tape cutter assembly 78 is clearly shown in FIGS. 3 and 5.

The tape cutters 106 are formed with sharp, burr-free cutting edges 148for cutting the ribbons of tape 70. In addition, the tape cutters 106include a finished surface (e.g., 8 micro inches). The guide openings108 in the cutter base 104 are also formed with finished surfaces. Thelocation of the tape cutters 106 with respect to the cutter block 122 iscontrolled by the guide openings 108 in the cutter base 104. Thereforethe clearance between the tape cutters 106 and the guide openings 108must be as small as possible but still maintain free sliding movement ofthe tape cutters 106 through the guide openings 108.

The mounting plate 134, mounting shoe 136 and tape cutters 106 areadapted to be driven up and down on the guide posts 144 by a hydrauliccylinder or other actuator (not shown). By way of example, areciprocating speed for the tape cutters 106 can be on the order of 4strokes per minute.

Referring to FIG. 3, during the operation of the tape cutting apparatus54, the tape feed rollers 72, 74 unwind the tape reels 68 in thedirections indicated by rotational arrow 150. The ribbons of tape 70move in a linear direction 98. The ribbons of tape 70 are driven by thetape feed rollers 72, 74 through the tape guide 76 and into the entrancechannels 114 (FIG. 6) in the tape cutter assembly 78.

Indexing of the ribbons of tape 70 by the tape feed rollers 72, 74 issuch that the tape 70 substantially fills the guide openings 108 (FIG.6) in the cutter base 104. The amount the tape 70 is indexed and thesize of the guide openings 108 are selected to provide a desiredfinished length for the cut decals 52. With a die attach area 24 of thesubstrate 14 positioned over the guide openings 108, the tape cutters106 are actuated to cut the tape 70 to form the decals 52. At the sametime that the edge 148 (FIG. 6) of the tape cutters 106 cuts the decals52, the end surfaces 132 (FIG. 6) of the tape cutters 106 press thedecals 52 against the heated substrate 14. The vacuum passages 128function to attach the decals 52 to the surface 132 of the cutters 106as the decals 52 are pressed against the substrate 14.

Once the decals 52 are cut and pressed against the die attach area 24 ofthe substrate 14, the tape cutters 106 are retracted. The polymer strip12 is then indexed to position another substrate 14 and die attach area24 over the guide openings 108 in the cutter base 104. The abovesequence is then repeated for forming and pressing decals 52 against theadjacent die attach area 24.

Using the tape cutting apparatus 54 the decals 52 are cut and appliedwithout wasted tape. In addition, the alignment openings 108 of the tapecutter assembly 78 align the tape 70 to the cutters 106, and also alignthe cut decals 52 to the substrate 14. The size of the decals 52 can bedetermined by selection of the width and index of the tape, and by thelength of the guide openings 108. In addition, the spacing between theguide openings 108 determines the spacing between the cut decals 52, andthe location of the decals 52 on the substrate 14.

Referring to FIGS. 7A-7C, steps in a method for fabricating a chip scalepackage 16CSP (FIG. 7B) in accordance with a second embodiment of theinvention are illustrated. As shown in FIG. 7B, the chip scale package16CSP comprises a substrate 14CSP, and a semiconductor die 10 attachedto the substrate 14CSP using decals 52A formed using a tape cuttingapparatus 54A (FIG. 7C) constructed substantially as previouslydescribed for tape cutting apparatus 54 (FIG. 3).

In the illustrative embodiment, the substrate 14CSP comprises silicon,but alternately can comprise ceramic, plastic or a glass filled resinsuch as FR-4. The substrate 14CSP can be initially provided on a siliconpanel 12CSP with a plurality of other substrates 14CSP. The siliconpanel 12CSP will subsequently be singulated by cutting or shearing alongseparation lines 164 into multiple chip scale packages 16CSP. Thesilicon panel 12CSP can have a size and peripheral configurationsubstantially similar to the polymer strip 12 (FIG. 1A) previouslydescribed. Alternately, the silicon panel 12CSP can have otherperipheral configurations such as square, circular, or the shape ofsemiconductor wafer blank.

As shown in FIG. 7B, the substrate 14CSP includes a die mounting recess152, and a wire bonding recess 154. The substrate 14CSP also includes apattern of conductors 156 in electrical communication with solder balls64 formed in a dense array (e.g., ball grid array) on a surface of thesubstrate 14CSP. Electrically insulating layers 158 comprising SiO₂, orother insulating material, insulate the bulk of the substrate 14CSP fromthe conductors 156. Also, wires 58 are bonded to the conductors 156 onthe substrate 14CSP, and to the die bond pads 56 on the die 10. Inaddition, a polymer die encapsulant 160 in the die mounting recess 152substantially encapsulates the die 10, and a polymer wire bondingencapsulant 162 in the wire bonding recess 154 substantiallyencapsulates the wires 58 and associated wire bonds.

Further details of the chip scale package 16CSP are disclosed incommonly assigned U.S. Pat. Nos. 5,674,785 and 5,739,585 to Akram etal., which are incorporated herein by reference.

For fabricating the chip scale package 16CSP, the silicon panel 12CSPcan be provided as shown on the left segment of FIG. 7A, with multiplesubstrates 14CSP having the die mounting recesses 152 and the wirebonding recesses 154 formed therein. The die mounting recesses 152 andthe wire bonding recesses 154 can be formed using an anisotropic etchprocess as described in the above cited '785 and '585 patents. Inaddition, the silicon panel 12CSP can be provided with the conductors156, which can be formed using a metallization process, such as CVD andetching, or electrodeposition, as described in the above cited '785 and'585 patents.

Next, as shown in the center segment of FIG. 7A, the decals 52A can beattached to the substrates 14CSP. The decals 52A can be formed andattached substantially as previously described.

As shown in FIG. 7C, a system 44A for fabricating the chip scale package16CSP includes a tape cutting apparatus 54A formed substantially aspreviously described for apparatus 54 and configured to cut the decals52A from ribbons of tape 70A, and to apply the decals 52A to thesubstrates 14CSP. The system also includes a substrate handlingapparatus 100B configured to handle and index the silicon panel 12CSPduring application of the decals 52A. The substrate handling apparatus100B can comprise a conventional leadframe handling apparatus. Asuitable leadframe handling apparatus is the previously identified model2000 CA manufactured by ESC Manufacturing, Inc., Ivyland, Pa.

Following attachment of the decals 52A to the substrates 14CSP, and asshown in the right segment of FIG. 7A, the dice 10 can be attached tothe decals 52A, and thus to the substrates 14CSP. Attachment of the dice10 can be performed with a die attacher as previously described.Following attaching of the dice 10, the wires 58 (FIG. 7B) can be wirebonded to the die bond pads 56 and to the conductors 156, and theencapsulants 160, 162 (FIG. 7B) can be formed in the die mountingrecesses 152 and the wire bonding recesses 154. These steps can beperformed as disclosed in the above cited '785 and '585 patents. Thepanel 12CSP can then be separated by cutting or shearing alongseparation lines 164 into individual chip scale packages 16CSP.

Referring to FIGS. 8A-8C, steps in a method for fabricating a multi chipmodule 16MCM (FIG. 8A) in accordance with a third embodiment of theinvention are illustrated. The multi chip module 16MCM comprises asubstrate 14MCM and a plurality of semiconductor dice 10A attached tothe substrate 14MCM using decals 52B formed using a tape cuttingapparatus 54B (FIG. 8C) constructed substantially as previouslydescribed for tape cutting apparatus 54 (FIG. 3).

In the illustrative embodiment, the substrate 14MCM comprises silicon,ceramic, or a glass filled resin such as FR-4. The substrate 14MCM canhave a size and peripheral configuration substantially similar to thepolymer strip 12 (FIG. 1A) previously described. Alternately, thesubstrate 14MCM can have other peripheral configurations. In addition,the substrate 14MCM can be similar in construction to a printed circuitboard, and can include other required electrical components such asresistors, diodes and capacitors.

Initially, as shown in the top segment of FIG. 8A, the substrate 14MCMcan be provided with die attach areas 24MCM. In addition, the substrate14MCM includes bond pads 168 and conductors 170 in electricalcommunication with an edge connector 172. For simplicity only a fewconductors 170 are illustrated. However, each bond pad 168 will be inelectrical communication with an associated conductor 170.

Next, as shown in the center segment of FIG. 8A, the decals 52B can beattached to the substrate 14MCM. The decals 52B can be formed andattached substantially as previously described using a system 44B. Asshown in FIG. 8C, the system 44B includes a tape cutting apparatus 54Bformed substantially as previously described for apparatus 54. The tapecutting apparatus 54 is configured to cut the decals 52B from ribbons oftape 70B, and to apply the decals 52B to the substrate 14MCM. The system44B also includes a substrate handling apparatus 100B configured tohandle and index the substrate 14MCM during application of the decals52B. The substrate handling apparatus 100B can comprise a conventionalsubstrate handling apparatus. A suitable substrate handling apparatus isthe previously identified model 2000CA manufactured by ESCManufacturing, Inc., Ivyland, Pa.

Following attachment of the decals 52B to the substrate 14MCM, and asshown in the right segment of FIG. 8A, the dice 10A can be attached tothe decals 52B, and thus to the substrate 14MCM. Attachment of the dice10A can be performed with a die attacher as previously described.Following attaching of the dice 10A, the wires 58 (FIG. 8B) can be wirebonded to the die bond pads 56, and to the conductors 170 on thesubstrate 14MCM.

Thus the invention provides an improved method and system forfabricating semiconductor components. While the invention has beendescribed with reference to certain preferred embodiments, as will beapparent to those skilled in the art, certain changes and modificationscan be made without departing from the scope of the invention as definedby the following claims.

What is claimed is:
 1. A system for fabricating a semiconductorcomponent comprising: a substrate configured to form a ball grid arraypackage, the substrate comprising an organic polymer and a plurality ofmetal conductors on the organic polymer; a tape cutter apparatusconfigured to cut a tape to form a decal and to apply the decal to thesubstrate, the decal having a first finished dimension equal to a widthof the tape and a second finished dimension equal to an indexed lengthof the tape; and a substrate handling apparatus configured to positionthe substrate proximate to the tape cutter apparatus during applying ofthe decal to the substrate.
 2. The system of claim 1, wherein thesubstrate comprises a first surface having the metal conductors thereonand a second surface having a die mounting area thereon for mounting thedie.
 3. The system of claim 1, wherein the substrate comprises aplurality of wire bonding pads and a plurality of ball bonding pads inelectrical communication with the metal conductors.
 4. The system ofclaim 1, wherein the substrate comprises a material selected from thegroup consisting of bismaleimide-triazine, epoxy and polyimide.
 5. Thesystem of claim 1, wherein the substrate is contained on a stripcomprising a plurality of substrates.
 6. A system for fabricating asemiconductor component comprising: a substrate configured to form amulti chip module, the substrate comprising a plurality of die attachareas and a plurality of conductors; a tape cutter apparatus configuredto cut and to apply a decal to each die attach area, the decal having afirst finished dimension equal to a width of the tape and a secondfinished dimension equal to an indexed length of the tape; and asubstrate handling apparatus configured to position the substrateproximate to the tape cutter apparatus for applying the decal.
 7. Thesystem of claim 6, wherein the substrate comprises a material selectedfrom the group consisting of silicon and ceramic.
 8. The system of claim6, wherein the substrate comprises a glass filled resin.
 9. The systemof claim 6, wherein the substrate comprises a plurality of wire bondingpads in electrical communication with the conductors.
 10. The system ofclaim 6, wherein the substrate comprises an edge connector in electricalcommunication with the conductors.
 11. A system for fabricating asemiconductor component comprising: a substrate configured to form achip scale package, the substrate comprising a first surface, a secondsurface, a plurality of die mounting areas on the first surface and aplurality of conductors on the second surface; a tape cutter apparatusconfigured to receive a length of tape, to cut the length of tape toform a decal, and to apply the decal to a die mounting area on thesubstrate; and a substrate handling apparatus configured to position thesubstrate proximate to the tape cutter apparatus for applying the decalto the die mounting area.
 12. The system of claim 11, wherein the decalhas a first finished dimension equal to a width of the tape and a secondfinished dimension equal to an indexed length of the tape.
 13. Thesystem of claim 11, wherein the substrate comprises a material selectedfrom the group consisting of bismaleimide-triazine, epoxy and polyimide.14. A system for fabricating a semiconductor component comprising: astrip comprising an organic polymer having a plurality of substratesthereon, each substrate configured to form a ball grid array package andcomprising a plurality of metal conductors on the organic polymer; atape cutter apparatus configured to cut a ribbon of adhesive tape toform a plurality of decals and to apply the decals to the substrates,the decals having a first finished dimension equal to a width of thetape and a second finished dimension equal to an indexed length of thetape; and a substrate handling apparatus configured to handle the stripand to locate the substrates proximate to the tape cutter apparatus forapplying the decals.
 15. The system of claim 14, wherein the substratecomprises a material selected from the group consisting ofbismaleimide-triazine, epoxy and polyimide.